1. Field of the Invention
This invention relates to a gas generating agent pack of an air bag inflation gas generator that is used to form a combustion chamber in the air bag inflation gas generator.
2. Description of the Prior Art
A prior shock absorber to protect a passenger car driver from shocks at a collision accident comprises an air bag having a capacity of, for example, 60 liters and a gas generator to inflate the air bag with gas. At a collision accident of a passenger car, explosives or other gas generating agents having a similar composition thereto, which are charged in the gas generator, are ignited and burnt to produce gas. The air bag is instantaneously inflated by the resultant gas to protect the driver against any collision shocks, thereby avoiding possible serious injury of the driver.
FIG. 7 shows a prior air bag inflation gas generator disclosed in Japanese Patent Application Laid-open Print No. 2-155857. In the drawing, the reference numeral 11 shows a combustion chamber containing a plurality of gas generating agents 13 in the stacked state.
The gas generating agents 13 are a circular plate having a through hole 15 at the center, and the through hole 15 accommodates an ignition agent 17.
These gas generating agents 13 are accommodated in a concealed container 19. At the center of this concealed container 19, a concave part 21 is formed to be depressed toward the through hole 15 of the gas generating agents 13.
In the concave part 21 is provided an igniter 23 to burn the gas generating agents 13.
The combustion chamber 11 has a combustion chamber filter 25 disposed along its inner wall. And, a plenum chamber 27 annually surrounds the combustion chamber 11 and receives gas flow through an orifice 26 from the combustion chamber filter 25.
The plenum chamber 27 contains a plenum chamber filter consisting of an upper filter 29 and a gas filter 31.
And, the plenum chamber 27 contains a gas outlet 33 to supply the gas flow from the gas filter 31 to an air bag.
In this type of air bag inflation gas generator, the powder in the igniter 23 burns the ignition agent 17 when the igniter is energized. The ignition agent 17 in turn causes the gas generating agents 13 to burn. Gas from the gas generating agents 13 flows into the plenum chamber 27 through the combustion chamber filter 19 disposed along the inner wall of the combustion chamber 11. The gas is then purified by the upper filter 29 and the gas filter 31 and flows into the air bag through the gas outlet 33. The air bag can be completely inflated within a very short time, for example, approximately 0.04 second.
The above prior air bag inflation gas generator, however, has drawbacks that the capacity of combustion gas of the gas generating agents 13 is limited and the combustion gas purifying performance is limited.
More specifically, when the air bag for a front passenger is inflated, because the front passenger seat has a different riding environment from the driver seat and a passenger takes various positions, and when a child takes the front passenger seat, physical features are different from an adult, requiring, for example, an air bag to have a large capacity of about 2.5 times of a conventional air bag for the driver seat. Therefore, it has been demanded that the combustion gas capacity of the gas generating agents is large and the gas generator for air bag inflation can purify the large volume of combustion gas surely.
The present inventor has filed an air bag inflation gas generator which has remedied the above problems (Japanese Patent Application Laid-open Print No. 4-146843).
As shown in FIG. 8, the above air bag inflation gas generator comprises forming combustion chambers 45, 46 for accommodating gas generating agents 43 by a partition member 47 on either end of a longitudinal cylindrical member 41 which has gas outlets 39 formed in its middle section 37, disposing a cylindrical final filter 49 inside the middle section 37 of the cylindrical member 41, disposing an intermediate filter 51 between the final filter 49 and the partition member 47 within the cylindrical member 41, and opening an orifice 53 in the partition member 47 on the side of the intermediate filter 51.
And, the combustion chamber 45 at one end and the combustion chamber 46 at the other end are connected by a fuse device 54 which ignites the gas generating agents 43 in the combustion chamber 46 at the other end a certain time after starting the combustion of the gas generating agents in the combustion chamber 45 at one end.
With this air bag inflation gas generator, the combustion gas capacity of the gas generating agents 43 can be increased by a large margin as compared with the prior art and a large volume of combustion gas can be surely purified.
Since this air bag inflation gas generator forms the combustion chambers 45, 46 for accommodating the gas generating agents 43 at both ends of the cylindrical member 41 by the partition member 47 and connects the combustion chambers 45, 46 by the fuse device 54, it has drawbacks that the device has a complicated structure and the ignition capacity lacks in reliability.